This invention relates to a single reagent system for use in determining the presence of commercially available adulterants in urine, or other fluids, being screened for drugs of abuse. This invention is particularly useful in automated analyzers used in screening for drugs of abuse.
As the use of illicit drugs in the workplace, public transportation, professional and amateur athletics and the like has grown, public concern for the health and safety of individuals, as well as concern for the negative impact of such drug use on productivity of industry, and its inherent economic impact, and the general well being and health of the community at large has grown as well. Such concern has led to the use of analysis of urine as a way to detect and deter drug use. Such testing for drugs of abuse in industry, as for prospective and current employees, military personnel, transportation, employees, professional and amateur athletes, as well as people under supervision of the criminal justice system, has become a relative common occurrence.
Because of the intrusive nature of such testing commonly performed by examining a urine sample, the testing procedure must withstand vigorous scrutiny. Since a positive test result of screening for drugs of abuse may have serious impact on the life of a person being tested, the incentive for the drug user to alter the test specimen is high. The users of drugs of abuse have developed a number of ways to adulterate the collected specimen, thus attempting to produce a false negative result in the drug screening test being conducted.
A user of drugs of abuse may attempt to affect the test results, thus producing a false negative test result, or upon occassion, a false positive result, as by: 1) dilution--efforts to reduce the drug concentration in the urine sample; b) substitution--substitution for liquids such as clean (that is, drug-free) urine, sosa, tea, apple juice for the drug-containing sample; or c) adulteration--addition to the urine specimen of foreign material in an attempt to invalidate the test.
Illicit drug users have learned to falsify urine screening tests by in vitro adulteration of urine sample by the addition of several readily available agents, including household products; i.e., Nacl, soap, such as hand or dish soap, bleach, finger nail polish remover, vinegar, Drano, NaNCO.sub.3, Visine, fingernail polish, Gold Seal Tea (available in natural food stores), or hydrogen peroxide (H.sub.2 O.sub.2), together with commercially available adulteration products, such as "Urine-Aid" (gluteraldehyde).
Additionally, users of drugs of abuse may eliminate some drugs more rapidly from their bodies by altering their urinary pH. Abusers of phencylidine or amphetamines may be treated with NH.sub.4 Cl to hasten detoxification, thus increasing the rate at which substances (phencylidine or emphetamines) are eliminated from their bodies. This treatment with NH.sub.4 Cl also results in lowering the pH of the user's urine.
While the use of some in vitro adulterants can be eliminated by the direct observation of the test subject during the collection process, such direct observation is often deemed unacceptable. In vivo adulternants represent an additional burden to the screening processor because they are consumed by the drug user several hours or days prior to screening of the sample, and can be detected only by laboratory means.
Such adulteration can affect all three commonly used methods for drugs of abuse, namely: florescent polarization immunoassay (FPIA), radioimmunoassay (RIA), and enzyme immunoassay (EMIT or EIA). Consequently, clinical chemistry literature recommends that testing for drugs of abuse in urine samples include testing for adulterants to identify urine samples which have been adulterated. See Mikkelsen and Ash, "Adulterants Causing False Negatives In Illicit Drug Testing", Clin. Chem. 34/11, 2333-2336 (1988); and Warner, "Interference of Common Household Chemicals In Immunoassay Methods For Drugs Of Abuse", Clin. Chem., 35/4, 648-651 (1989).
Accordingly, a need exists for providing an easy and convenient manner by which to make a determination of the presence of adulterants in urine samples which are being tested for drugs of abuse. A further need exists for a convenient manner by which such determinations may be made in conjunction with an automatic analyzing process for drugs of abuse.